Google Classroom comments (from Kacey Bell blog:

Class Comments for Whole Class Feedback and Communication

If enabled in the settings of your class in Google Classroom, class comments offer a way for students and teachers to communicate and collaborate in a way that the entire class can view. Class comments will appear in the stream, as well as give students and teachers to option to reply in the stream. This can be really useful for general feedback and questions. I use class comments to respond to frequently asked questions about assignments. You know when you keep hearing the same question from your students all day. 

Use the class comments feature to respond to questions and give general guidance on assignments, clarify any instructions, and increase communication in your class. Encourage students to use this tool! Let them know it’s okay to use the class comments to ask questions, and that you will respond promptly. This can serve as an FAQ for your students, and the students who are reluctant to ask questions will have it to refer to.

To Enable Class Comments, go to the Gear shift, and use the drop down to select from the following options: “students can post and comment,” “students can only comment,” or “only teacher can post and comment.” (It’s important to note here that “post” means to allow students to add their own posts with ideas, questions, or other things they wish to share with the entire class.)

In the stream, add the class comment in the space provided below the assignment, announcement, or discussion. Class comments look almost identical from the teacher and student views.

**All Class Comments can be viewed in the stream and on the assignment page.

Private Comments for Individual Student Feedback

I have seen a lot of teachers and students confused by the differences in class comments versus private comments. Private comments DO NOT appear in the stream. Private comments are just between the teacher and students.

Add a Private Comment (Student View)

To leave a private comment, the student must “open” the assignment or click on the title and leave the private comment at the bottom of the “Your Work,” window. Only the teacher can view the private comments left by students.

Add a Private Comment in Google Classroom

View a Private Comment (Teacher View)

Finding private comments can be a little tricky for the teacher. To view private comments, go to the assignment details page by clicking on the title of the assignment in the stream or from the “work” page. From here you can see thumbnails of your students’ work. To the left, you will see your roster, and a snippet of the private comment if there is one. Click on the student’s name to view the private comment.

View Private Comments in Google Classroom

Discussion Questions in Google Classroom

Discussion questions are an excellent way to engage students in online conversation, debate, and collaboration. I also love the way Google Classroom allows students to see and respond to each other, but first requires that they submit their own answer before they are allowed to view the rest of the students’ answers. This encourages original answers and deters cheating.

Comments are NOT Answers to Discussion Questions

This is a common misunderstanding that I have seen in using Google Classroom. My students don’t understand where to respond to a discussion question when class comments are enabled. I end up with answers in two different places: as class comments and as responses to the question. Be sure you instruct your students to open the assignment and respond where indicated below.

Student responses to discussion in Google Classroom